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This species has been observed on Reunion, Mayotte and Madagascar Islands

Order : Pleurobranchomorpha Superfamily :Pleurobranchoidea Family : Pleurobranchidae Distribution : Indo West Pacific Maximal size : 35 mm Abundance : From time to time : on the rocky coast and on the fore reef zone Species characteristics : It has a smooth surface yellow to orange- coloured. Two cylindrical rhinophores and two oral tentacles attached to either side of an oral veil are visible on the head White spots are sometimes present on the dorsum. The back is covered in small white acid gland cells which secrete a milky white defensive secretion
	Showing species characteristics...	Photo Philibert Bidgrain Reunion, Etang salé, 5 January 2005, size : 10-15 mm

See more about : Sightening and mating periods

See more about : Berthellina citrina variability in Southwest Indian ocean

Remarks :

Synonymous (according worms):
              - Pleurobranchus citrinus Rüppell & Leuckart, 1828
              - Pleurobranchus punctatus Quoy and Gaimard, 1832     

Bibliographic data :

This is a "side-gilled" slug or pleurobranch, because they have their gill on the right side of the body, usually hidden in the space on the right side of the body between the upper mantle and the foot     It has a small flat shell remnant ( size : 8 mm for a specimen of 22 mm), hidden in the mantle skin above the digestive gland. Berthella and Berthellina have a so thin and fragile internal shell that we can only find them in the living animal.     Species of Berthellina have often been reported to feed on sponges but Bertsch & Johnson (1981) reported that in Hawaii they also eat various corals ( Tubastrea coccinea, Leptastrea sp. and Porites lobata )     Living in permanant pools or on the reef ( 0 to 10-15 m). During the day it hides under rocks but is active at night.     The egg ribbon is orange

References :

Bill Rudman Seaslug site : Sea Slug Forum : Berthellina citrina
   Nudipixel Berthellina citrina

Publications :

Moustafa, A.Y., Golestani, H. & Valdés, Á. Mar Biodiv (2016). https://doi.org/10.1007/s12526-016-0558-2
    Rüppell E. & Leuckart F.S. (1828-1830). Mollusca [in] Atlas zu des Reise im Nordlichen Afrika von Eduard Rüppell. 1. Abth. Zoologie. 5. Neue wirbellose Thiere des Rothen Meers. Frankfurt, H.L. Brönner pp. 1-22, pl. 1-12 [1828], pp. 23-47 [probably 1830]
    Willan, R.C. (1984). A review of diets in the Notaspidea (Mollusca: Opisthobranchia). Journal of the Malacological Society of Australia, 6 : 125-142. (for Berthellina citrina...)

Other photos of Berthellina citrina :

Philibert Bidgrain Reunion, Etang salé, on the lagon, less 1 m, 30 January 2007, size : 20-25 mm. An pale orange form... This is a "side-gilled" slug or pleurobranch, because they have their gill (a) on the right side of the body, usually hidden in the space on the right side of the body between the upper mantle and the foot

Emmanuel Eby Reunion, Saint Leu, 10-15 m, 26 September 2004 A yellow form... Small pale yellowish dots (a) are visible on the notum.

Philibert Bidgrain Reunion, Etang salé, on the rocky coast, less 1 m, 24 August 2006, size : 25 mm. An orange form...

Hugues Flodrops Reunion, Etang salé, on the rocky coast, less 1 m, 5 May 2007, 18 and 35 mm.. We can clearly see the small internal shell An intense orange form...

Alexandre Laporte Madagascar, Sainte Marie, Antafondro Lodge Lagoon, less 1 m, 1 September 2017, size : 15 mm

See more about : Berthellina citrina variability in Southwest Indian ocean

Reunion, two Berthellina citrina , at Saint Gilles, by Sonia Ribes Beaudemoulin

Reunion, Berthellina citrina and Hexabranchus sanguineus, at Etang salé, by Philibert Bidgrain 

Reunion, oral veil of Berthellina citrina , at Etang salé, by Christophe Cadet 

Mayotte, one pale orange form of Berthellina citrina , at Sakouli, by Matthias Deuss